1. Field Of The Invention
The present invention relates to zeolite-impregnated nonwoven polymer pads useful for filtering and removing ammonia from fluids and for enhancing plant growth and microbial activity, and methods of producing such zeolite-impregnated pads. In addition, the present invention is directed to methods for removing ammonia from fluids, methods for growing plants in situ and methods for growing bacteria using the zeolite-impregnated pads.
2. Description of the Prior Art
It is known in the biological arts that a significant function of animal metabolism is to eliminate or excrete ammonia and other toxins from the body. However, when toxins are eliminated into or are already present in a relatively enclosed environment, such as enclosed air spaces and finite areas of water or land, such as aquariums, fish ponds, cages, carrying cases and other relatively confined animal habitats, toxins may readily be reingested. Toxins and other waste products may accumulate and become odiferous and offensive. In fish aquariums, for example, ammonia is a pervasive and persistent toxin causing fish illness and death. Ammonia is continually being produced in the aquarium environment by decaying food, decaying solid waste matter, fish respiration and fish urine. Ammonia accumulates in a typical aquarium environment and becomes increasingly dangerous to fish health. Conventional methods for removing or neutralizing ammonia include the use of zeolite in the form of loose chips in an aquarium filter container through which aquarium water must pass as the water is being filtered. Such methods, however, are generally inconvenient and inefficient because the proper amount of zeolite chips must be measured and added to the aquarium filter container. The zeolite chips are also difficult to remove and replace.
Other methods are somewhat objectionable in that they require the addition of chemicals which are costly and potentially dangerous to aquarium animals and plants.
Waste elimination from animals is another example where ammonia and similar nitrogenous compounds generally result in noxious odors, in particular ammonia odor. Such odors are particularly acute in enclosed areas, such as buildings and homes. Conventional methods to deodorize or filter odors form air include U.S. Pat. Nos. 3,776,188 and 3,898,324 concerning inhibiting the formation of odors from poultry farms. These patents disclose the use of a dried fine powder of zeolite mixed with a coarse powder of crystalline ferrous sulfate hepta-hydrate. The use of zeolites in these patents is to impart stability, while the deodorizing is accomplished by the sulfate hepta-hydrate.
In U.S. Pat. No. 4,256,728, zeolites are used as support for an acid, such acid serving as the deodorization agent.
U.S. Pat. No. 4,059,543 discloses the use of clinoptilolite, a zeolite, in the ammonia exchanged form and treated with a dilute solution of a strong acid to act as an absorbent for acid gases.
Zeolites are known to possess excellent adsorption capacity for nitrogen as contained in ammonia and other nitrogenous chemicals as well as positively charged minerals, including calcium, iron, magnesium and copper, among others. The zeolite absorption mechanism is an ion exchange system whereby ammonium ions and other ions having similar positive charges are ionically bonded to the zeolite surface. Where zeolite is ground into a fine powder form, there is a high surface area of zeolite to which ammonia and other compounds and minerals may become adsorbed. However, zeolite powders are difficult to use efficiently without some form of containment that does not adversely affect zeolite activity and does not overly compromise the advantageous high zeolite surface area.
U.S. Pat. No. 4,437,429 discloses the use of hydrated zeolite for controlling odors emanating from pet litter, such as cat litter. This patent discloses the use of a pad of sorptive sheet material filled with zeolite. The adsorptive and other chemical properties of zeolites in general are also disclosed by this patent. Nothing in this patent, however, discloses the use of zeolite in environments other than animal litter, such as aquatic and land environments.
Nitrogenous chemicals are known nutrient sources or fertilizers for plants and nitrifying bacteria. Fertilizers, such as urea, are generally available as granulated powders or liquids which may be added to plant habitats to enhance plant growth. However, such fertilizers are generally inconvenient and inefficient because the proper amount of fertilizer must be added and may, especially in aquatic environments, cause cloudiness of the water and may harm animal life present therein.
Bio-Chem Beads.TM. biological filter material, available from Aquarium Pharmaceuticals, Inc., provides a physical habitat for nitrifying bacteria in microporous beads. Such beads, however, have no chemical attraction for ammonia and other nitrogenous compounds and do not, therefore, supply a nutrient source for nitrifying bacteria or a medium where such nutrients may be concentrated.
In view of the deficiencies and inefficiencies of the prior art, it would be desirable to have a zeolite-containing pad which may be used to remove or neutralize ammonia and other chemicals and minerals from fluid and land environments and/or used to enhance plant and microbial growth, which is relatively simple to produce, easy to use and effective.